He doesn't look like he's suffering. The crook in his tail looks like it's behind the swim bladder and most vital organs. I see no reason to cull him. He looks like he can still lvev a happy fishy life even if he is a humpback. :)

Thanks for you conserns for my little Crook. He/She (I think a she now) is happy as can be and was actually the biggest of the fry for a while. She seems to be able to swim just fine too. ;)
When I saw that crook in her tail for the first time I worried that I might have to cull her. So I kept a close eye on her for a while. No problems came up that I saw. She swam and ate just like the others. So I was relieved that I wouldnt have to cull her after all. :D